The effects of β-lapachone on gastric secretion were investigated. The pylorus of male Sprague-Dawley rats was ligated and intraduodenally injected with β-lapachone, and the volume, pH, free HCl, and total acidity of gastric fluid were measured 6 hours after the operation. Treatment with β-lapachone resulted in dose-dependent inhibition of gastric secretion Gastric fluid was reduced to 42.9% of control level by 100 mg/kg of β-lapachone, leading to an increase of pH to 6.70 from 1.85 in the control group. In parallel with the increase of pH, at this dosage, free HCl and total acidity decreased to 16.7% and 12.0%, respectively, of control levels. β-Lapachone exhibited ED50 values of 72, 46, and 47 mg/kg for inhibition of gastric volume, free HCl, and total acidity, respectively, implying a superior efficacy on gastric acid to volume. In comparison, pantoprazole (30 mg/kg) reduced the volume, free HCl and total acidity of gastric fluid to 53.0%, 26.0%, and 25.0%, respectively, of control levels, resulting in an increase in pH to 6.36. In the current study, it was confirmed that β-lapachone at an appropriate dose (100 mg/kg) exerted a higher inhibitory effect on gastric secretion than pantoprazole (30 mg/kg), a well-known proton-pump inhibitor. Therefore, it is suggested that β-lapachone could be a candidate compound for prevention or treatment of gastric ulcers induced by diverse psychological and physical stimuli.

This study was conducted in order to evaluate the effect of sericin-calcium (SC) as therapy for ovariectomy-induced osteoporosis in rats. Three weeks after ovariectomy (OVX), Sprague-Dawley rats were divided randomly into three groups: sham-operated group (Sham), ovariectomized group, and SC-treatment group (OVX+SC). Rats in the OVX+SC group were given drinking water containing 0.07% SC for eight weeks. Bone breaking force, mineralization, and blood parameters related to bone metabolism were analyzed. In OVX animals, blood concentration of 17β-estradiol showed a significant decrease, while osteocalcin and type I collagen C-terminal telopeptides (CTx) showed an increase. Breaking force of femurs as well as bone mineral density (BMD), ash, calcium, and phosphorus in femurs showed a significant decrease following OVX. Treatment with SC (0.07% in drinking water) resulted not only in remarkable restoration of the decreased 17β-estradiol and increased osteocalcin and CTx concentrations, but also led to recovery of decreased femoral breaking force, BMD, ash, calcium, and phosphorus. It is suggested that SC effectively improves bone density by preventing bone turnover-mediated osteocalcin, CTx, and minerals, and that it could be a potential candidate for use in therapy or prevention of post-menopausal osteoporosis.

Effects of carnitine on atherosclerosis and steatosis of hypercholesterolemic rabbits induced by a high-cholesterol diet (HCD) containing 0.5% cholesterol and 2.0% corn oil were investigated. Male New Zealand white rabbits with hypercholesterolemia (blood cholesterol 1,000-1,500 mg/dl) induced by two-week feeding a HCD, were fed a HCD containing 0.008 or 0.075% L-carnitine for an additional eight weeks. Feeding a HCD for 10 weeks resulted in severe atheromatous change, covering 55.7% of the aortic walls, in addition to profound hepatic steatosis. However, carnitine supplementation resulted in recovery of the increased low-density lipoproteins and triglycerides and a decrease in the levels of high-density lipoproteins following HCD feeding, although the increased cholesterol concentration was not potentially attenuated. Notably, carnitine induced a marked reduction of the atheroma area and hepatic lipid accumulation as well as lipid peroxidation. The results of this study indicated that carnitine exerted anti-atherosclerotic and fatty liver-preventing activities through blockade of lipid peroxidation and regulation of lipid metabolism.

The effects of isotonic saline on corneal penetration, thickness, and injury, as well as lacrimal secretion in a rat model of dry eye were investigated, in comparison with distilled water. Male Sprague-Dawley rats received intraperitoneal administration of atropine sulfate (20 mg/kg) and their eyes were exposed to dry (relative humidity 25-35%) air flow (2.4 m/sec), under Zoletil anesthesia, for 5 hr to induce dry eye. During the period of dry eye induction, distilled water or isotonic saline (5 μl) was instillated onto the cornea every 30 min. Corneal penetration was measured through fluorescein dye quantification, and corneal thickness and injury were examined under a microscope. Lacrimal (tear) secretion and mucin-like glyocoprotein excretion from goblet cells were measured using the Schirmer test and microscopy, respectively. In dry eye rats treated with distilled water, corneal thickness, tear secretion, and mucin-like glycoprotein excretion were decreased to 74.0%, 74.1%, and 46.3% of normal levels, respectively, resulting in marked corneal injury and a significant increase in corneal penetration. In comparison, treatment with isotonic saline resulted in recovery of lacrimal secretion, in spite of a slight improvement of mucin-like glycoprotein excretion, and thereby prevented corneal penetration of fluorescein by 10%. The results indicate that repeated instillation of isotonic saline could provide slightly greater protection from corneal injury, compared with distilled water by facilitating lacrimal secretion, in addition to relief of inconvenience and pain.

This study was conducted in order to investigate repeated-dose toxicities of Magnolia ovobata ethanol extract (MEE). MEE was administered orally to male and female Sprague Dawley rats at dose levels of 0, 500, 1,000, or 2,000 mg/kg for four weeks. Repeated administration of MEE did not induce abnormalities in general signs, body weight gain, feed and water consumption, necropsy findings, or organ weights. In addition, no abnormality was observed in hematological analyses; red blood cells and their indices, white blood cells, platelets, and coagulation times. In male rats, BUN and creatinine showed an increase at doses of 2,000 mg/kg and 500-1,000 mg/kg, respectively, while in female rats, lactate dehydrogenase and creatine phosphokinase showed a decrease at 2,000 mg/kg, the upper-limit dose of repeated-dose toxicity studies. However, there were no dose-dependent increases or gender-relationship. In addition, other parameters of the hepatic and muscular toxicities as well as energy and lipid metabolism were not affected. In microscopic examination, no considerable pathological findings were observed. The results indicate the safety of oral administration of MEE to the upper-limit dose.